JPS6123626Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a speed control device for self-propelled working machines such as power shovels and bulldozers.

In recent years, there has been a trend towards regulating the noise emitted by self-propelled working machines in urban areas, but the engine operating noise is a very large factor in this noise, and each part of the working machine is ultimately driven by the engine. Therefore, by keeping the engine speed below a certain intermediate speed, the noise generated by the self-propelled work machine can be kept within the permissible range. Since it is not necessary, there is no problem in terms of work function.

By providing a simple spring mechanism, this invention prevents the engine speed from increasing above a certain intermediate speed except when driving in a straight line, making it possible to carry out work in urban areas with low noise, and also enables work on vast work sites. This also made it possible to drive at high speeds.

The present invention is a self-propelled work machine in which the travel operation levers that control the crawler drive devices on both sides can be simultaneously operated in a straight line with one hand. In order to automatically return the accelerator lever, which has been rotated from the speed position to the high speed side, to the constant intermediate speed position when no external force is applied, an engaging member that is separably engaged with the accelerator lever is attached to a constant position on the chassis side. It is characterized in that it is constantly activated to return along the guide member until it hits the intermediate speed position regulating stopper.

An illustrated embodiment in which the present invention is applied to a two-pump type hydraulic power shovel will be described below. Reference numeral 1 denotes a vehicle platform rotatably mounted on support frames for both crawlers 2, 2, 3 a boom cylinder for lowering a boom 4 whose base end is pivoted on the chassis 1, and 5 pivotably mounted on the tip of the boom. An arm cylinder that rotates the arm 6; 7 a bucket cylinder that rotates a bucket 8 pivotally mounted on the tip of the arm; 9 a driver's cab on the chassis 1; 10 a high-speed diesel engine mounted on the chassis; Inside the operator's cab 9, there are rollers 2 on both sides,
travel control levers 11, 11 of the directional control valves for controlling the drive hydraulic motors 2, 12, the control lever 12 of the directional control valve for controlling the boom cylinder 3, the control lever 13 of the directional control valve for controlling the bucket cylinder 7, and the arm cylinder. An operating lever 14 for the directional switching valve for controlling the vehicle chassis 1, an operating lever 15 for the directional switching valve for controlling the hydraulic motor for controlling the chassis 1, and an accelerator lever 16 are attached to the travel operating levers 11, 11, respectively. The auxiliary grip 11a that can be operated with one hand in the same direction at the same time is installed symmetrically, and the engine 10 drives two constant displacement hydraulic pumps of equal capacity, one of which is used as the second hydraulic pump. Pressure oil is supplied to the directional switching valve that is switched by the operating levers 11, 12, and 13 on the left half of Figure 4, and the other hydraulic pump supplies pressure oil to the directional switching valve that is switched by the other operating levers 11, 14, and 15. What we are doing is the same as before.

Further, the accelerator lever 16 is pivoted to the side of the operation lever group so that it can be operated at least simultaneously with the traveling operation levers 11, 11 on both sides, and the accelerator lever 16 is attached to the chassis 1 via a connecting rod 17. engine 10
The mechanical governor 18 is connected to the speed control lever 19 of the mechanical governor 18, and there is a large rotational frictional resistance between the boss portion 16a of the accelerator lever 16 rotatably attached to the pivot shaft 20 and the support member 21 of the pivot shaft 20. By holding the spring plate 22 in such a way as to produce the following, the accelerator lever 16 is fixed at an arbitrary rotation position against the force of the governor spring (tension spring) 23 to return the speed control lever 19 to the engine idling position 0. This is the same as before. Note that 24 and 25 are speed control levers 1
A stopper 26 for regulating the rotation limit of the accelerator lever 9 is an arcuate scale plate that indicates the rotation angle of the accelerator lever 16.

Reference numeral 27 denotes an engaging member that is separably engaged with the accelerator lever 16, and the engaging member 27 includes a piston portion 27a and a piston rod portion that are slidably fitted into a cylindrical guide member 28 fixed on the chassis 1. 27b, and an engagement plate portion 2 attached to the tip of the piston rod portion so that its axial position can be adjusted.
7c, a compression spring 29 is compressed and clamped between the piston portion 27a and the end of the cylindrical guide member 28 on the piston rod insertion side, so that the accelerator lever 16 rotated above a certain intermediate speed position N is not affected by external force. During operation, the engaging member 27 is returned to its original position against the rotational frictional resistance of the accelerator lever by the spring plate 22 until the piston portion 27a hits the constant intermediate speed position regulating stopper 28a that closes the opposite end of the cylindrical guide member 28. Make it.
In the illustrated case, the lower end of the engagement plate portion 27c is slidably supported on the vehicle chassis 1, and a contact roller 16b is attached to the lower end of the accelerator lever 16 that engages with the engagement plate portion.

According to the above configuration, the accelerator lever 16 is moved to the constant intermediate speed position N or from this to the idling position 0.
When the accelerator lever is rotated in the direction of
can be driven at any speed, and the accelerator lever 16 can be moved from a constant intermediate speed position N to a maximum speed position M.
the spring 2 through the engagement member 27.
When the engine speed is increased while compressing 9, when the accelerator lever operation is stopped, the engagement member 27 returns to its original position due to the elasticity of the spring 29 until it hits the stopper 28a, and the accelerator lever 16 is moved against the rotational frictional resistance. Return to constant intermediate speed position N.

Therefore, by setting the constant intermediate speed position N to a speed position corresponding to the noise tolerance limit when working in urban areas, it is possible to perform excavation work by operating any two of the operating levers 12 to 15. , any one of the operation levers and the auxiliary grip 1 of the both-side traveling operation levers.
1a and 11a at the same time to perform part of the work while moving straight, both hands are occupied and the accelerator lever 16 cannot be operated, so the noise generated by the self-propelled work machine is not acceptable when working in urban areas. In addition, when moving the self-propelled work machine straight, one hand simultaneously controls both auxiliary grips 11a, 11a, and the other hand rotates the accelerator lever 16 toward the maximum speed position M. The accelerator lever 16 can be moved at high speed by moving the self-propelled work machine, and when rotating the both-side travel operating levers 11, 11 in opposite directions, such as when rotating the interlining of a self-propelled work machine, the accelerator lever 16 is removed from the hand. Since the self-propelled working machine automatically returns to the constant intermediate speed position N, there is no risk of the self-propelled working machine falling over.

In the above-described embodiment, the accelerator lever 16 is fixed at any rotational position by frictional resistance, so that the operating force required to rotate the accelerator lever against the elasticity of the spring 29, which is greater than the frictional resistance. However, if you want to avoid this, it is possible to provide sawtooth-like unevenness along the circumferential direction on the arcuate scale plate 26 between the ON positions, and to constantly engage the sawtooth-like unevenness with a spring. The spring plate 22 is removed and the elasticity of the spring 29 is reduced by attaching the engaged element to be biased to the accelerator lever side so that the rotational resistance of the accelerator lever between positions ON is significantly greater than the rotational resistance of the accelerator lever between positions NM. It suffices to make it weaker, and the present invention also covers this case.

[Brief explanation of the drawing]

Fig. 1 is a side view of an embodiment of the present invention showing the main parts in cross section, Fig. 2 is a longitudinal sectional front view of the accelerator lever mounting part, Fig. 3 is a side view of the self-propelled work machine, and Fig. 4 is the operating lever. FIG. 1... Chassis, 2... Crawler, 4... Boom,
6...Arm, 8...Bucket, 9...Driver's cab,
10...Engine, 11...Travel operation lever, 1
2, 13, 14, 15...operation lever, 16...accelerator lever, 17...removable lever, 18...mechanical governor, 19...speed control lever, 2
2... Spring plate, 27... Engaging member,
28... Cylindrical guide member, 28a... Constant intermediate speed position regulating stopper, 29... Compression spring.

Claims (1)

[Scope of utility model registration request] In a self-propelled work machine in which the travel operation levers that control the crawler drive devices on both sides can be operated simultaneously in a straight line with one hand, the accelerator lever is attached to the chassis so that it can be operated simultaneously with the travel operation lever, and the accelerator lever is installed on the chassis so that it can be operated simultaneously with the travel operation lever, and The accelerator lever rotated to the high speed side,
In order to automatically return to the constant intermediate speed position when no external force is applied, an engaging member that is separably engaged with the accelerator lever is constantly returned along the guide member until it hits a constant intermediate speed position regulating stopper on the vehicle chassis side. A speed control device for a self-propelled working machine, characterized in that